This small catapult was designed throw objects over short to medium distances. I deliberately made it more complicated than it had to be, adding a crank to pull the arm back and a clutch that when pulled, releases the arm. The gearing is set up to provide a mechanical advantage, meaning that the crank is rotated several times for every one rotation of the arm.

This view of the catapult shows the exterior finish. Birch plywood was used as the main material, which I accented with walnut trim and veneer to hide the plywood end grain.

When ready to fire, a rubber band is hooked around the metal eye, and the crank is turned clockwise. When the arm is fully pulled back, a wooden pin is pulled, releasing the arm.

To pull the arm back, I designed a gear arrangement that gives a mechanical advantage. The gearing is set up to give a low velocity/high torque output (the arm) with a high velocity/low torque input (the crank). This means that the crank must be turned several times for every one rotation of the arm.

Here, the clutch mechanism can be seen. The axle that extends to the exterior on the left hand side can be pulled out, disengaging the gears, and allowing the catapult to swing forward freely.